WHO alarmed about the spread of dengue

News release

Manila, 23 July 2007—The World Health Organization (WHO) has warned that the Western Pacific Region may be heading for a major dengue outbreak unless concerted effort and cooperation are undertaken quickly.

The geographical reach of dengue, already entrenched in many tropical countries, has greatly expanded over the last 30 years, primarily as a result of the invasion into new areas by Aedes aegypti, the principal mosquito most likely to carry dengue. This year the disease, which arrived earlier than usual, has already caused hundreds of deaths in the Region.

Between 1991 and 2004, ten countries and areas — Cambodia, China, French Polynesia, Fiji, Malaysia, the Lao People's Democratic Republic, New Caledonia, the Philippines, Singapore and Viet Nam — accounted for 98.4% of all dengue cases and 99.7% of all deaths in the Western Pacific Region. Current official information from most WHO Member States is incomplete, making it difficult to get an accurate estimate of the magnitude of the problem in the Western Pacific Region.

Dengue is now endemic in at least 100 countries. About 40% of the world's population, or about 2.5 billion people, are at risk throughout the tropics and subtropics. Over 50 million dengue infections, including about 400 000 cases of dengue haemorrhagic fever, are estimated to occur annually. Dengue haemorrhagic fever is a leading cause of childhood death in many endemic countries.

WHO is calling for stronger political commitment and greater investment of resources from Member States, and commitment by other key stakeholders, to support dengue prevention and control programmes. This involves increased dengue surveillance during and between outbreaks; proper management of patients, especially complicated cases, in public and private health facilities; reduction of breeding sites; outbreak preparedness; sharing of information; and mobilization of the public.

Dr John Ehrenberg, WHO Regional Adviser in Malaria, Other Vectorborne and Parasitic Diseases, said tracking dengue statistics and information is difficult, as many cases and outbreaks may not be officially reported. Official information would allow neighbouring countries and areas to anticipate and plan for increased dengue surveillance and to take precautionary measures. Countries are therefore encouraged to provide information to WHO on dengue activity and to make sure political commitment and resources are in place to support dengue prevention programme activities.

"Factors leading to the spread of dengue include population explosion, migration and rapid growth of urban areas, which place a heavy strain on public health services and access to drinkable water," said Dr Ehrenberg. "People exposed to these settings often rely on containers to collect water for their own drinking supply. These containers can become mosquito-breeding sites. Water storage practices are therefore a key target of dengue prevention and control programmes."

Although intense efforts are under way to develop a vaccine, there currently is no vaccine to prevent dengue nor are there any effective antiviral drugs to treat the disease. Thus, WHO has called for an integrated approach to dengue fever prevention and control.

A biregional dengue strategic plan is being developed with involvement of Member States, the WHO Regional Offices for the Western Pacific and South-East Asia, and other key stakeholders. The plan is based on the broader framework of the Asia-Pacific Strategic Plan for Dengue (2007-2015). WHO is actively supporting Member States in planning and implementing dengue prevention and control activities.

For more information, please contact the Public Information Office at (632) 528 9991or 93 or email PIO_Unit@wpro.who.int

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